In today's highly interconnected computing environments, a single customer can require a myriad of network configurations. For example, a customer can have internal networks called Intranets, external networks to other sites of the customer or to other organizations called Extranets, and the customer can have one or more Virtual Private Networks (VPNs). Each different VPN can be considered a separate network configuration. The customer can also have Internet network configurations to provide access to the World Wide Web (WWW).
Each network configuration (e.g., Intranet, Extranet, VPN, Internet, and others) will have its own data addressing scheme and policies that the customer must maintain and manage. As one of ordinary skill in the art readily appreciates this is not a trivial exercise. Moreover, often the customer may desire to have different network configuration interface with one another (e.g., an Extranet with an Intranet, and the like). This adds a layer of complexity in managing the customer's network configurations since the addressing schemes and policies between disparate network configurations are often not compatible with each other.
As a result, customers have turned to Service Providers (SPs) to manage and outsource the customers' networks. To do this, a customer's network site uses a customer edge device (CE). The CE can be any host computing device and/or a routing device for transferring network traffic from the customer's site to the SP. Network traffic occurs as data packets transmitted over a data link (e.g., Gigabit Ethernet (GigE), Frame Relay (FR), Time-Division Multiplexing (TDM), Asynchronous Transfer Mode (ATM), and others). The SP receives the data packets at a Provider Edge device (PE), which is another host computing device and/or routing device.
Typically, a customer will lease hardware from a SP, in order to manage the outsourced network configurations. The SP uses an Internet Protocol (IP) backbone to interface network traffic to the CE. Further, routing tables (RIBs) and forwarding tables (FIBs) are uniquely assigned to each of the customer's network configurations in order to effectively relay network traffic within the PE. Thus, the SP provisions separate routing devices for the customer to accommodate each of the customer's network configurations. As one of ordinary skill in the art readily appreciates, this becomes expensive for a customer, especially as the number of network configurations increase at the customer's site.
To address these problems, the Internet Engineering Task Force (IETF) promulgated a standard referred to as Request for Comments (RFC) number 2547 (RFC2547). RFC2547 defines methods by which a SP with an IP backbone can more efficiently provide VPNs (e.g., network configurations) for its customers. RFC2547 uses Multiprotocol Label Switching (MPLS) and Border Gateway Protocol (BGP) for distributing routes of network traffic over the IP backbone. Each network configuration (e.g., VPN) occurring within the SP's PE includes a Virtual Routing and Forwarding Module (VRFM) that has its own unique RIB and FIB for acquiring routes and forwarding data packets. The disparate RIBs, between VRFMs, exchange routes using BGP. VRFMs enable a VPN exchange using BGP to provide VPN routing. Data between the VRFMs is transmitted as labeled packets over a backbone tunnel.
Yet, RFC2547 requires a single unique RIB and FIB for each VPN. Moreover, a VPN interface (e.g., VPN communication protocol originating from a VPN site) that is associated with a VPN exchange communicates with a single VRFM. Thus, in RFC2547, each additional VPN interface requires a different instantiation of a VRFM to handle the additional VPN interface. Thus, each VRFM can support only one VPN. Furthermore, RFC2547 does not address how a VPN site can be enabled to access the Internet. As is readily apparent to one of ordinary skill in the art, these limitations impact the scalability of the RFC2547 standard since the mapping between the RIBs, FIBs, and VPN interfaces are symmetric with the VRFMs. Moreover, the features of the VRFMs cannot be distributed to other devices within the SP's PE.
Therefore, there is a need for improving existing PE methods and systems, so that the features of the RFC2547 standard and other VPN provisioning models can be fully utilized in a scalable fashion with a distributed PE. Such improvements can permit a single CE to communicate with a single PE over a single CE to PE interface channel while using a variety of disparate VPN. With such improvements, the VPNs can intercommunicate, as desired by the customer, within the distributed PE over a single CE to PE interface channel.